[C++知识库]《C语言程序设计现代方法：第2版 修订版》第四章课后编程题

《C语言程序设计现代方法：第2版 修订版》第四章课后编程题，水平有限，仅供参考。
1

#include <stdio.h>

int main (void)
{
	int number,new_number;
	
	printf("Enter a two-digit number:");
	scanf("%d",&number);
	
	new_number=(number%10*10)+(number/10);
	
	printf("The reversal is:%3d",new_number);
	
	return 0;
}

2

#include <stdio.h>

int main (void)
{
	int number,new_number;
	
	printf("Enter a three-digit number:");
	scanf("%d",&number);
	
	//这题处理三位数 
	new_number=((number%100)%10)*100+(number%100)/10*10+(number/100);
	
	printf("The reversal is:%3d",new_number);
	
	return 0;
}

3

#include <stdio.h>

int main (void)
{
	int hundres,tens,ones;
	
	printf("Enter a three-digit number:");
	scanf("%1d%1d%1d",&hundres,&tens,&ones);	
	printf("The reversal is:%d%d%d",ones,tens,hundres);
	
	return 0;
}

4

#include <stdio.h>

int main (void)
{
	int number,fr,se,th,fo,fif;
	
	//8的5次方是32768 
	printf("Enter a number between 0 and 32767:");
	scanf("%5d",&number);
	
	fr=number/4096;
	se=number/512;
	th=(number-se*512)/64;
	fo=(number-se*512-64*th)/8;
	fif=number%8;
	
	printf("In ocral, your number is: %1d%1d%1d%1d%1d",fr,se,th,fo,fif);
	
	return 0;
}

5

#include <stdio.h>

int main (void)
{
	int i1,i2,i3,i4,i5,i6,i7,i8,i9,i10,i11,first_sum,second_sum,total;
	
	printf("Enter the first 11 digits of a UPC: ");
	scanf("%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d",&i1,&i2,&i3,&i4,&i5,&i6,&i7,&i8,&i9,&i10,&i11);
	
	first_sum=i1+i3+i5+i7+i9+i11;
	second_sum=i2+i4+i6+i8+i10;
	total=3*first_sum+second_sum;
	
	printf("Check digit: %d\n",9-((total-1)%10));
	
	return 0;
}

6

#include <stdio.h>
 
int main (void)
{
	int i1,i2,i3,i4,i5,i6,i7,i8,i9,i10,i11,i12,first_sum,second_sum,total;
	
	printf("Enter the frist 12 digits of an EAN: ");
	scanf("%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d",&i1,&i2,&i3,&i4,&i5,&i6,&i7,&i8,&i9,&i10,&i11,&i12);
	
	first_sum=i2+i4+i6+i8+i10+i12;
	second_sum=i1+i3+i5+i7+i9+i11;
	total=3*first_sum+second_sum;
	
	printf("Check digit: %d\n",9-((total-1)%10));
	
	return 0;
}